Kei Yuki

Kei Yuki is a member of Harlock's crew aboard the Arcadia, serving as chief navigator and science officer. She is already part of the crew when Tadashi comes aboard and is described as the second-youngest crew member after him.

Different additions to the franchise portray her romantic feelings differently: she initially seems to have a crush on Tadashi, while later additions portray her as inclined toward Harlock.